package com.cyc.forkJoin;

import java.util.concurrent.RecursiveTask;

/**
 * 求和计算的任务
 * 如何使用forkJoin
 * 1.ForkJoinPool 通过它来执行
 * 2.计算任务ForkJoinTask
 */
public class ForkJoinDemo extends RecursiveTask<Long> {
    private Long start;
    private Long end;
    //临界值
    private Long temp = 10000L;

    public ForkJoinDemo(Long start, Long end) {
        this.start = start;
        this.end = end;
    }
    @Override
    protected Long compute() {
        if ((end-start)<temp){
            Long sum = 0L;
            for (Long i = start; i <= end; i++) {
                sum += i;
            }
            return sum;
        }else {
            //forkJoin 递归
            long middle = (start+end)/2;
            ForkJoinDemo task1 = new ForkJoinDemo(start,middle);
            task1.fork();//任务拆分，把任务压入线程队列
            ForkJoinDemo task2 = new ForkJoinDemo(middle+1,end);
            task2.fork();
            return task1.join()+task2.join();
        }
    }
}
